This invention relates to a guide roller apparatus in a rotary press that uses a paper roll and more particularly to a guide roller apparatus that can prevent wet ink, immediately after printing, from piling on the circumferential surfaces of the guide rollers or that can clean the wet ink from the guide roller surfaces.
The piling of ink on the guide roller's circumferential surfaces in the rotary press is a serious problem in the printing process. Various measures to solve this problem have been employed.
For example, as shown in the Japanese Utility Model Application Publication No. 22312/1961, the circumferential surfaces of the guide rollers are made rough and irregular so that they will not easily collect oily materials. Another example is the Japanese Utility Model Application Publication No. 26946/1964, in which the circumferential surfaces of guide rollers are provided with air blowing openings to form a layer of air between the guide rollers and the web of paper thereby reducing the contact area between the paper web and the guide rollers' circumferential surfaces or the chance of their contact to prevent ink from piling on the rollers. Still another example is the Japanese Patent Application Laid-Open No. 149449/1987, in which the guide rollers are connected with a drive means or a braking means to control the rotation of the guide rollers at circumferential speeds different from the speed of the running paper web to rub the guide roller surfaces with the paper web, thus preventing the ink from piling and cleaning the roller surfaces.
Of the above measures employed in the conventional rotary press to prevent ink from piling on the guide roller circumferential surfaces, the one that reduces the contact area between the paper web and the guide roller circumferential surfaces or reduces the contact chance, is not sufficiently effective as the printing speed and the amount of printing have increased in recent years. Thus, the rotary press using this preventive measure requires manual efforts in cleaning the guide roller surfaces of the piled ink. This poses two problems--low efficiency, i.e., a large number of man-hours are required, and hazardous environment to which maintenance workers are exposed as the guide rollers are usually installed at high locations.
In the rotary press using a measure where the guide rollers run at circumferential speeds different from the speed of the running web to rub the guide roller circumferential surfaces with the paper web and thereby prevent ink from piling on the roller surfaces to keep them clean, the problems presented by the abovementioned countermeasure are solved. However, this measure requires a drive means and a means to control the circumferential speeds of the guide rollers. Since the rotational force transmitted from the running web to the circumferential surface of the guide roller various depending on an enwrap angle at which the web is wound around the guide roller's circumferential surface, it is necessary to restrict the rotation of each guide roller with a properly controlled braking force. This in turn requires a brake for each guide roller and a braking force adjusting means for each brake, increasing the facility cost.